Aspergillosis is a severe fungal infection that most frequently involves the lungs in people who have immune deficiency caused by cancer chemotherapy and/or transplantation. Although good drugs are available, establishing a diagnosis is difficult, and late treatment has limited our progress in decreasing morbidity and mortality. We observed that Aspergillus polysaccharide antigens are excreted in urine in animal models and humans with disease. Using a novel monoclonal Ab that detects galactofuranose-containing Aspergillus antigens in urine, we have developed a diagnostic test that relies on lateral flow technology, enabling use at near point-of- care. Results of proof-of-concept studies suggest that this device detects antigens early during the course of disease. This phase I application is developed to address two aims: 1. To determine the performance characteristics of this prototype assay when used as an aid to diagnose suspected infection; and 2. To determine the performance characteristics of this assay when used to screen high-risk patients for early disease. Successful validation of the assay will enable phase II development for use of this novel assay in screening and early treatment strategies.